#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>


int main() {
    int n = 0;
    int sum = 0;
    float average = 0.0f;
    int i = 0;
    for (i = 1; i <= 5; i++)
    {
        scanf("%d", &n);
        sum = sum + n;
    }
    average = sum / 5.0;
    printf("%.1f", average);
    return 0;
}
